Mobile crane having a double-armed jib



Nov. 15, 1966 H. BROZIAT 3,285,445

MOBILE CRANE HAVING A DOUBLE-ARMED JIB Filed April 23, 1965 5 Sheets-Sheet 1 210 j I o INVENTOR. #orsi- Bra 1/411,

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Nov. 15, 1966 BRQZW 3,285,445

MOBILE CRANE HAVING A DOUBLE-ARMED JIB Filed April 23, 1965 5 Sheets-Sheet 2 Fig.5

Z"" Z 54 Kl/Zn 9 1:3 IIiI INVENTOR. Horst B/ OZ [at BY; Hi

NOV. 15, 1966 oz 3,285,445

MOBILE CRANE HAVING A DOUBLE-ARMED JIB Filed April 23, 1965 5 Sheets-Sheet 3 INVENTOR.

Horst Broziaf United States Patent 0,

3 285 445 MomLa CRANE nAviNd A DOUBLE-ARMED JIB Horst Broziat, Radolfzeller Strasse 44, Allensbach (Bodensee), Germany Filed Apr. 23, 1965, Ser. No. 450,291 Claims priority, application Germany, Apr. 27, 1964,

76,530 Claims. (Cl. 212-38) The present invention relates to a mobile crane, wherein at the upper end of a foldable crane column a doublearmed jib is swingably mounted with a load receiving means at one end about a vertical and horizontal axis with the use of an immovable rim coaxially surrounding the foot of the crane column, the rim having a carriage moving thereon. The carriage is connected by means of a rope pull with the end of the jib pointing in the direction opposite the load hook and the load receiving means is connected by means of a rope pull, the free end of which, as well as the end of the rope pull serving the purpose of moving in the jib, is guided through the hollow crane column by means of an extension of the crane column projecting beyond the folding axis of the crane column to a winch for each rope pull immovably mounted on a running gear.

It is one object of the present invention to provide a mobile crane amounting to an improvement of known crane structures whereby in addition to a greater overhang and lifting height it is made possible that the crane is also capable of lifting loads in its folded position. This is of extreme importance upon hauling heavy loads through low entrance paths.

It is still another object of the present invention to provide a mobile crane, wherein the arm of the doublearmed jib assuming the load is longer than the crane column. bearing during support of the load in case the crane is in its folded position.

It is still a further object of the present invention to provide a mobile crane, wherein an eye is provided at the rear end of a vehicle carrying the crane outside of the coaxially disposed rim for securing the load hook. Furthermore, at the end of the jib directed toward the load receiving means is provided a slide-rail or on the rearward upper edge of the coaxially disposed rim a slide roller is provided for the purpose to simplify the sliding of the jib along the coaxially disposed rim during its move into its erected position.

It is yet another object of the present invention to provide a mobile crane, wherein the yielding of the wheel axle of the vehicle is eliminated, contrary to known structures, not only downwardly to the ground, but also upwardly toward the chassis, so that the vehicle side remote from the load can be used as a counter weight, while otherwise the vehicle spring remote from the load still assists in an enlargement of the inclined position of the crane.

It is still a further object of the present invention to provide a mobile crane, which includes an improvement in the locking of the crane column in its upright position, as well as a forced drive of the carriage.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

The crane column can thereby be locked on its 3,285,445 Patented Nov. 15, 1956 FIG. 3 is a fragmentary, schematic top plan view of the co-axial rim around the crane column, together with a Windlass drive, drawn to a somewhat larger scale;

FIG. 4 is a vertical section through the coaxial rim with the Windlass, shown on a larger scale; H

FIG. 5 is a vertical, fragmentary section through the locking mechanism between the truck axle and the chassis, shown on a larger scale; and

FIG. 6 is a sectional view across the lower end of the crane column, showing its locking mechanism on a larger scale.

Referring now to the drawings, the mobile crane comprises a truck chassis 1, the rear portion of which carries a rim 4 having a double T-profile and fitted with a base plate 51 (FIGS. 3 and 6). The rim 4 surrounds coaxially a crane column 7 and its bearing block 6 by means of a pivot pin 8 (FIGS. 1 and 3). The rim 4 serves .for guiding a movable Windlass 19 (FIGS. 3 and 4) to be described later in greater detail.

The upper end of the crane column 7 carries a conventional, rotatable head 10 having a horizontal swivel axis 11 for a double-armed jib 12. One arm 12a of the jib 12 is longer than the crane column 7, so that it projects beyond the rear end of the truck, and, thereby, a load hook 13 suspended from the arm 12a is interlocked in an eye member 28a disposed at the rear end of the truck, in the folded position of the crane column 7.

It should be noted that in previously known crane devices of this kind the load-bearing arm of the jib had to be kept shorter than the crane column itself with a view to avoid collision between the front end of the protruding arm and the coaxial rim.

The arrangement according to the present invention makes, on the one hand, for a substantial crane overhang and lifting height, and, on the other hand, permits loads to be hauled when the crane is folded down. Unwanted erecting of the tilted down crane column, owing to the load applied to the protruding jib, is prevented by the provision of an appropriate locking means, for instance a locking pin (not illustrated) on a forward stay or support 29 for the crane column 7 and forming part of the truck chassis.

By the expedient of hooking the load hook 13 into the eye 28a, power-actuated erecting of the crane is also made possible with the aid of a winch 17 to which the cable 14 fed from the load hook 13 is guided through the hollow crane column 7. By comparing the respective FIGURE 1 is a schematic side elevation of the mobile FIG. 1, the column being shown in a turned-down position;

positions shown in FIGS. 1 and 2, it will be understood that the crane column 7 acts as a double-armed lever which pivots about its suspension 8. The longer, normally upper portion of the column 7 with its head 10 and swivel axis 11 will come to rest, in its folded or tilted position, upon the support 29.

When the crane is being erected, the load-carrying end of the arm 12a could collide with the rearmost upper edge of the coaxial rim 4. To prevent such occurrence, preferably a slide roller 30b is provided on the rim 4; alt-er- .natively, the arm 12a may carry a slide rail 3011 (both expedients being shown in FIGS. 1 and 2).

A cable 18 connects the roller 21a at the end of the shorter jib arm 12b to the afore-mentioned Windlass 19 and to a cable winch 21b connected therewith (FIG. '4). In a known manner, this mechanism serves for the vertical movement of the jib 12, that is, its pivoting movement about the axis 11; a motor 23 (FIG. 4) operates the cable winch 21b. For preventing flexural loads to be imparted to the column 7, and also to keep its weight within reasonable limits, additional tensioning means may be provided between the rotatable head 10 and the Windlass 19, shown, for example, as a cable 31.

In case of a relatively small load carried by the arm 12a the pressure applied by driving wheels 20 (FIG. 4)

of the windlass 19 may be too small on the coaxial rim 4 to move the Windlass therealong without slip. To this end, the Windlass 19 is moved forcibly by an endless chain 33 (FIG. 3) engaged by a chain wheel 35 and driven by a motor 36 (FIGS. 1 and 2), the chain 33 being guided by rollers 34 along the inner periphery of the coaxial rim 4. The Windlass 19 is always located on the side or" the column 17 opposite the load and is also fitted with a counterweight 32 which substantially increases the stability of the crane.

Both the stability and the vertical adjustment of the crane are improved, particularly on an uneven terrain or ground, by the provision of a special wheel support or strutting 37 (FIG. this structure being omitted from FIGS. 1 and 2 for the sake of clarity. This support 37 renders the spring suspension of the truck ineffective, so that not only the elastic path between the wheel axis and the ground, but also the path between the axis and the chassis is rendered ineffective. The chassis portion in the region of vehicle axle 52, opposite the truck end at which the load is located, acts as a counterweight. In previously known structures of this kind, the path is disactivated only between the Wheel axle and the ground, and there is thus a series danger that the elastic wheel suspension opposite the load actually aids in bringing the crane into or increasing its tilted position.

Referring now to FIG. 5, the wheel support 37 consists of two telescoping members provided between the truck axle 52 and the chassis portion 54, including a bar member 38 on the axle 52 and a bushing 39 on the portion 54 of the chassis 1. In the manner of a Vernier division, these elements are provided with respective bores, namely passages 40a in the bar 38 and bores 40 in the bushing 39. As a matter of example, there are ten bores 40 along the same distance which accommodates nine passages 40a, allowing a fine adjustment'of the wheel support depending upon which bore will take up an arresting bolt 53. Preferably, one of the bores, e.g. 40a, may be given a somewhat wider play or tolerance. There will always be a coincidence between a particular pair of bores, so that the support 37 can be used to immobilize and counteract the spring action of the truck suspension. I

With reference to FIG. 6 (details of which are not shown in the small-scale views of FIGS. 1 and 2 and only schematically in FIG. 3), a locking system is now described for immobilizing the erected column 7. So far a bolt passed through the lower portion of the crane has been used for this purpose, requiring an operator on the truck itself.

In contradistinction, the crane according to the present invention features a cylindrical bushing 42 attached to the lower, pivoted end of the column 7. Inside the bushing 42 there is a locking bolt 41 having a conically tapering lower end 41a. By the action of a compression spring 45, resting upon the upper shoulder of the locking bolt 41, the end portion 41a may be urged into a conical sleeve 46 secured to or across the base plate 51 of the stand 6 in a manner registering with the afore-mentioned bushing 42, when the column 7 is erected.

Upon moving the column 7 about the pivot 8 in the direction of the arrow 55 (FIG. 6), a pawl 56 pivotally secured inside the column 7 abuts with its lower limb on a stationary stop 43, whereby a safety locking pin 44 is released from its normally engaged position within a recess 58 of the locking bolt 41 across registering bores in the walls of the column 7 and the bushing 42. The action between the elements 43 and 56 has to overcome the biasing force of a spring 57 acting upon the upper limb of the pawl 56. Once the locking pin 34 is released or withdrawn, the locking bolt 41 with its conical end portion 41a is allowed to move downward, as viewed in FIG. 6, into locking engagement with the conical sleeve 46, the removal of the safety locking pin 44 being obtained by any conventional means.

Before tilting the crane column 7, the bolt 41 has to be withdrawn from the sleeve 46 against the action of its compression spring 45. This can be accomplished by conventional electro-mechanical, hydraulical or pneumatical means. In the embodiment disclosed in FIG. 6, the bolt 41 is mechanically connected by way of a piston rod 59, with a piston 60 of a lifting pressure cylinder 47 actuated by compressed air. The latter may be fed into the cylinder 47 underneath the piston 60 from a compressedair tank by means of a magnetically operated valve 48.

It is important that the releasing and folding of the crane column 7 takes place only when the column is under the control of the cable 14 and the winch 17. This will prevent uncontrolled collapsing or tilting of the column 7 with the jib 12 attached thereto.

The electric control circuit of the truck-mounted crane (the circuit not being shown otherwise) includes a safety switch 49 in series connection with an actuating switch 50. The former is operatively connected to the eye 28a (FIGS. 1 and 2), so that the control circuit for the lifting cylinder 47 (illustrated in FIG. 6) is not completed unless the load hook 13 is securely attached to the eye 28a. By operating the Winch 17, the above-described cable 14 will allow the column 7 and the jib 12 to be safely and slowly lowered until the column 7 rests on the stay or support 29, as shown in FIG. 2.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. A mobile crane comprising a truck chassis,

support means movably secured to said truck chassis,

a tiltable crane column carried at its bottom end by said support means,

a circular rim surrounding coaxially said column, when in its vertical position, and a Windlass moving on said rim,

a double-armed jib rotatably and swingingly secured to the top end of said crane column,

one arm of said double-armed jib being a load-bearing arm,

means for selectively erecting said column into an upright position, and into a tilting-down position, respectively, the latter position being substantially parallel with said truck chassis,

said load-bearing arm of said jib being longer than said crane column, so as to protrude therebeyond in said tilting-down position,

said support means includes stationary stay means at a location of said truck chassis spaced apart from said crane column, for supporting the latter in said tilting-down position,

locking means disposed between said stay means and said crane column for immobilizing the latter and preventing its unwanted erecting movement,

said selective erecting and tilting means includes winch means acting on a cable guided through said column and said load-bearing arm,

a load hook being attached to said cable beyond said load-bearing arm, and further comprising,

eye means attached to a peripheral portion of said truck chassis,

said cable serving for the selective raising and lowering of loads applicable to said load hook, on the one hand, and for the erecting and tilting of said column, on the other hand, when said load hook is engaged in said eye means,

slide roller means attached to a peripheral portion of said truck chassis for preventing said cable and said load hook from damaging said support means in said tilting-down position, and

slide rail means attached to the free end of said loadbearing arm for abutting with a portion of said crane column in said tilting-down position.

2. The foldable crane, as set forth in claim 1, which includes a lateral bushing secured to the bottom end of said crane column for abutting contact with said slide rail means;

rotatable head means interposed between said top end of said crane column and said jib, forming a swivel axis therefor,

said selective erecting and tilting means includes tensioning means interposed between said head means and said support means, and serving to adjust a pre determined tilt to said crane column with respect to said support means; and

said support means further includes a counterweight on the side of said crane column opposite that of said load-bearing arm.

3. The foldable crane, as set forth in claim 1, further comprising locking means operable in said operative position between two members,

one of said members being constituted by said support means and the other of said members by said crane column,

said locking means includes a sleeve on one of said members and a reciprocable bolt on the other of said members movable into mating relation with said sleeve for immobilizing said crane column.

4. The foldable crane, as set forth in claim 3, in which said support means includes a plate to which said sleeve is secured,

a bushing is attached to said crane column at a location registering with that of said sleeve in the operative position,

said locking means further includes biasing means for urging said bolt into said mating relation,

said locking means further includes a safety mechanism between said support means and said column, for preventing movement of said bolt toward said sleeve except when said bushing registers with said sleeve,

said locking means further includes drive means for withdrawing said bolt into said bushing before said crane column is being tilted into said tilting-down position;

said drive means includes a hydraulic piston operable to withdraw said bolt,

electric circuit means for energizing said piston only under predetermined safe operating conditions;

hook means attached to a peripheral portion of said chassis, and in which,

said electric circuit means includes switch means closed when a pull is being exerted on said hook means.

5. The foldable crane, as set forth in claim 1, further comprising means for counteracting and rendering ineffective re silient forces between said chassis and the wheel axle thereof,

said counteracting means including a pair of members respectively attached to said chassis and said axle, as Well as a bolt by which selected pairs of bores can be interconnected in said members;

the member attached to said chassis is constituted by a bushing and the member attached to said axles is constituted by a bar telescopable in said bushing,

the bores in said members are disposed in vernier fashion,

said bolt can be passed into selected pairs of said bores for immobilizing said truck chassis with respect to said axles;

traction means for displacing said windlass on said rim means,

said traction means is constituted by an endless chain,

and further comprising rotating means for said crane column and said windlass, including rollers for guiding said chain on said rim means.

7/1961 France. 1/1958 Germany. 4/ 1961 Germany.

ANDRES H. NELSEN, Primary Examiner.

EVON C. BLUNK, Examiner.

A. L. LEVINE, Assistant Examiner. 

1. A MOBILE CRANE COMPRISING A TRUCK CHASSIS, SUPPORT MEANS MOVABLY SECURED TO SAID TRUCK CHASSIS, A TILTABLE CRANE COLUMN CARRIED AT ITS BOTTOM END BY SAID SUPPORT MEANS, A CIRCULAR RIM SURROUNDING COAXIALLY SAID COLUMN, WHEN IN ITS VERTICAL POSITION, AND A WINDLASS MOVING ON SAID RIM, A DOUBLE-ARMED JIB ROTATABLY AND SWINGINGLY SECURED TO THE TOP END OF SAID CRANE COLUMN, ONE ARM OF SAID DOUBLE-ARM JIB BEING A LOAD-BEARING ARM, MEANS FOR SELECTIVELY ERECTING SAID COLUMN INTO AN UPRIGHT POSITION, AND INTO A TILTING-DOWN POSITION, RESPECTIVELY, THE LATTER POSITION BEING SUBSTANTIALLY PARALLEL WITH SAID TRUCK CHASSIS, SAID LOAD-BEARING ARM OF SAID JIB BEING LONGER THAN SAID CRANE COLUMN, SO AS TO PROTRUDE THEREBEYOND IN SAID TILTING-DOWN POSITION, SAID SUPPORT MEANS INCLUDES STATIONARY STAY MEANS AT A LOCATION OF SAID TRUCK CHASSIS SPACED APART FROM SAID CRANE COLUMN, FOR SUPPORTING THE LATTER IN SAID TILTING-DOWN POSITION, LOCKING MEANS DISPOSED BETWEEN SAID STAY MEANS AND SAID CRANE COLUMN FOR IMMOBILIZING THE LATTER AND PREVENTING ITS UNWANTED ERECTING MOVEMENT, SAID SELECTIVE ERECTING AND TILTING MEANS INCLUDED WINCH MEANS ACTING ON A CABLE GIUDED THROUGH SAID COLUMN AND SAID LOAD-BEARING ARM, A LOAD HOOK BEING ATTACHED TO SAID CABLE BEYOND SAID LOAD-BEARING ARM, AND FURTHER COMPRISING, EYE MEANS ATTCHED TO A PERIPHERAL PORTION OF SAID TRUCK CHASSIS, SAID CABLE SERVING FOR THE SELECTIVE RAISING AND LOWERING OF LOADS APPLICABLE TO SAID LOAD HOOK, ON THE ONE HAND, AND FOR THE ERECTING AND TILTING OF SAID COLUMN, AND THE OTHER HAND, WHEN SAID LOAD HOOK IS ENGAGED IN SAID EYE MEANS, SLIDE ROLLER MEANS ATTACHED TO A PERIPHERAL PORTION OF SAID TRUCK CHASSIS FOR PREVENTING SAID CABLE AND SAID LOAD HOOK FROM DAMAGING SAID SUPPORT MEANS IN SAID TILTING-DOWN POSITION, AND SLIDE RAIL MEANS ATTACHED TO THE FREE END OF SAID LOADBEARING ARM FOR ABUTTING WITH A PORTION OF SAID CRANE COLUMN IN SAID TILTING-DOWN POSITION. 